1. Field of the Invention
The present invention relates to a method for producing a foamed article that includes a supporting element, a layer of foamed material, and a sewn upholstery cover applied on the layer of foamed material.
The present invention has been developed with particular regard to the field of production of foamed articles for vehicles, such as for example dashboards, upholstered panels for doors and the like. The invention relates in particular to the production of foamed articles provided with upholstery covers made of natural leather or fabric, or sewn quality upholstery covers.
2. Description of the Related Art
Foamed articles for vehicles, such as for example certain dashboards, comprise a supporting element made of rigid plastic material, an upholstery covering and a layer of foamed plastic material set between the upholstery covering and the supporting element made of rigid plastic material. The production of articles of this sort is obtained using a foaming die including a bottom die and a plunger, which, in a closed position, define a foaming cavity, injected and polymerized in which is a plastic foaming material, usually a polyurethane foam.
In the majority of cases, the upholstery cover is not of a sewn type. When the upholstery cover is not of a sewn type, it is applied on a positioning surface of the bottom die of the foaming die and is withheld in contact with said surface by suction. The supporting element of rigid plastic material is positioned on the plunger and the foaming die is closed. Foaming material is then injected in a foaming cavity formed between the upholstery cover and the supporting element.
In the case of particularly high-quality foamed articles, the upholstery cover is formed by cutting and sewing of a plurality of lengths of upholstery cover of quality material, such as for example natural leather, fabric, or embroidered covers. In these cases, it is not possible to use the method envisaged for non-sewn upholstery covers. The main problem in the case of sewn upholstery covers is the precise positioning of the rows of stitching (which have a major importance from the aesthetic standpoint) on the surface of the foamed article. The method used with non-sewn upholstery covers, which envisages setting the upholstery cover on the surface of the bottom die, is not able to ensure the precision necessary for positioning of the rows of stitching of the upholstery cover with respect to the finished article.
When it becomes necessary to provide an upholstery cover for dashboards or other foamed articles for vehicles according to the known art a foamed article is first produced without upholstery cover, and then the sewn upholstery cover is applied on the foamed article with additional operations of upholstery that envisage the use of glue for fixing the sewn upholstery cover on the layer of foamed material. These operations are basically of an artesanal nature and involve a high cost. Another drawback of the known art is that in order to provide vehicles with standard furnishing having non-sewn upholstery covers and with optional furnishing having sewn upholstery covers made of quality material, the automobile company must provide two different foaming dies; otherwise, the components with quality upholstery cover would have a greater thickness than those with non-sewn upholstery covers and would not be compatible with the housings of the foamed article provided according to design.